The Japanese Defense Ministry says what is believed to have been a Russian helicopter has violated Japanese airspace off the northern-most prefecture of Hokkaido.

The Defense Ministry says the helicopter intruded into Japanese airspace off Nemuro Peninsula at around 12:44 p.m., on Tuesday. The Air Self Defense Force scrambled fighter jets.

Ministry officials say the helicopter stayed inside the airspace for a very short time. They say the helicopter's flight route and other facts indicate it was Russian.

It is the first time since March 2022 that the ministry has publicized an intrusion incident involving a Russian aircraft or one suspected of being Russian, and the 43rd time since the Soviet era.

The Defense Ministry says it has lodged a protest with the Russian government through diplomatic channels.

The ministry is analyzing the purpose of the flight, while continuing to monitor activity of Russian aircraft.